U.S. patent number 10,465,617 [Application Number 15/736,332] was granted by the patent office on 2019-11-05 for dual-fuel internal combustion engine.
This patent grant is currently assigned to GE Global Sourcing LLC. The grantee listed for this patent is GE Jenbacher GmbH & Co OG. Invention is credited to Dino Imhof, Georg Tinschmann.
United States Patent |
10,465,617 |
Imhof , et al. |
November 5, 2019 |
Dual-fuel internal combustion engine
Abstract
A dual-fuel internal combustion engine including a regulating
device for regulating the internal combustion engine, at least one
piston-cylinder unit, at least one fuel injector for a gaseous
fuel, which is assigned to this piston-cylinder unit, at least one
gas supply device for gaseous fuel, which is assigned to this
piston-cylinder unit, whereby the regulating device has a pilot
operating mode in which the liquid fuel is introduced as a pilot
fuel, whereby the regulating device in pilot operating mode has a
transient mode in which, in an expansion phase of the
piston-cylinder unit, the piston-cylinder unit is supplied with
liquid fuel by the fuel injector.
Inventors: |
Imhof; Dino (Baden,
CH), Tinschmann; Georg (Schwaz, AT) |
Applicant: |
Name |
City |
State |
Country |
Type |
GE Jenbacher GmbH & Co OG |
Jenbach |
N/A |
AT |
|
|
Assignee: |
GE Global Sourcing LLC
(Norwalk, CT)
|
Family
ID: |
56463960 |
Appl.
No.: |
15/736,332 |
Filed: |
June 17, 2016 |
PCT
Filed: |
June 17, 2016 |
PCT No.: |
PCT/AT2016/050212 |
371(c)(1),(2),(4) Date: |
December 14, 2017 |
PCT
Pub. No.: |
WO2016/205843 |
PCT
Pub. Date: |
December 29, 2016 |
Prior Publication Data
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|
|
|
Document
Identifier |
Publication Date |
|
US 20180320608 A1 |
Nov 8, 2018 |
|
Foreign Application Priority Data
|
|
|
|
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Jun 23, 2015 [AT] |
|
|
A 399/2015 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F02D
19/061 (20130101); F02D 19/105 (20130101); Y02T
10/36 (20130101); Y02T 10/30 (20130101); F02D
19/0689 (20130101) |
Current International
Class: |
F02D
19/10 (20060101); F02D 19/06 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
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2698342 |
|
Jun 2010 |
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CA |
|
602 16 437 |
|
Sep 2007 |
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DE |
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10 2014 000 326 |
|
Jul 2014 |
|
DE |
|
10 2014 004 976 |
|
Oct 2014 |
|
DE |
|
1 730 394 |
|
Jul 2011 |
|
EP |
|
2 562 399 |
|
Feb 2013 |
|
EP |
|
2 806 140 |
|
Nov 2014 |
|
EP |
|
01/59280 |
|
Aug 2001 |
|
WO |
|
03/027473 |
|
Apr 2003 |
|
WO |
|
2012080568 |
|
Jun 2012 |
|
WO |
|
Other References
Imhof, D., et al., Dual Fuel combustion control and fast transient
response, GE co-pending Application No. AT 530/2015, filed on Aug.
13, 2015. cited by applicant .
Office Action and Search issued in connection with corresponding AT
Application No. A399/2015 dated May 27, 2016. cited by applicant
.
International Preliminary Report on Patentability issued in
connection with corresponding PCT Application No. PCT/AT2016/050212
dated Dec. 26, 2017. cited by applicant.
|
Primary Examiner: Tran; Long T
Attorney, Agent or Firm: McCoy Russell LLP
Claims
What is claimed is:
1. A dual-fuel internal combustion engine, comprising: a regulating
device for regulating the internal combustion engine, a
piston-cylinder unit, a fuel injector for a diesel fuel, coupled to
the piston-cylinder unit, and a gas supply device for gaseous fuel,
coupled to the piston-cylinder unit, wherein the regulating device
has a pilot operating mode in which the diesel fuel is introduced
as a pilot fuel injection by the fuel injector to initiate
combustion of gaseous fuel supplied to the piston-cylinder unit by
the gas supply device, wherein the regulating device in the pilot
operating mode has a transient mode in which, in an expansion phase
of the piston-cylinder unit, the piston-cylinder unit is also
supplied with an expansion phase injection of the diesel fuel by
the fuel injector while heat is released from the combustion of the
gaseous fuel, wherein the expansion phase injection occurs after
peak heat release.
2. The internal combustion engine according to claim 1 wherein, in
the pilot operating mode, the regulating device is configured to
switch from a steady-state operating mode to the transient mode
when a current load requirement changes beyond an absolute
threshold value.
3. The internal combustion engine according to claim 2 wherein, in
the pilot operating mode, the regulating device is configured to
switch from the transient mode to the steady-state operating mode
when approaching a new load requirement up to a predetermined
distance.
4. The internal combustion engine according to claim 1, wherein the
internal combustion engine is operated in lean operation with the
gaseous fuel and the diesel fuel of the pilot fuel injection
providing a combustion air ratio lambda of 1.7 to 1.8.
5. The internal combustion engine according to claim 1, wherein the
internal combustion engine is coupled to a stationary platform.
6. The internal combustion engine according to claim 1, wherein the
internal combustion engine is in a marine vehicle.
7. A method for operating a dual-fuel internal combustion engine,
comprising: supplying gaseous fuel to a piston-cylinder unit of the
internal combustion engine; during a steady-state phase,
introducing diesel fuel to the piston-cylinder unit as a pilot fuel
injection before top dead center of an expansion phase of the
piston-cylinder unit to initiate combustion of the gaseous fuel;
and responsive to operating in a transient phase, introducing the
diesel fuel to the piston-cylinder unit as the pilot fuel injection
and also as an expansion phase injection in the expansion phase of
the piston-cylinder unit while heat is released from combustion of
the gaseous fuel.
8. The method according to claim 7, further comprising, responsive
to the operation in the transient phase, changing a position of a
wastegate and/or a compressor bypass in a direction of a smaller
opening.
9. The method according to claim 7, wherein the steady-state phase
includes a current load demand changing by less than an absolute
threshold value and the transient phase includes the current load
demand changing beyond the absolute threshold value.
10. The internal combustion engine according to claim 1, wherein
the regulating device in the pilot operating mode has a
steady-state operating mode in which, in the expansion phase of the
piston-cylinder unit, the piston-cylinder unit is not supplied with
the expansion phase injection of diesel fuel by the fuel
injector.
11. The internal combustion engine according to claim 1, wherein
the regulating device, in the pilot operating mode, supplies
gaseous fuel to the piston-cylinder unit from the gas supply
device.
12. A system for a dual-fuel internal combustion engine, the system
comprising: a piston-cylinder unit; a fuel injector for injecting a
diesel fuel to the piston-cylinder unit; a gas supply device for
supplying gaseous fuel to the piston-cylinder unit; and a
regulating device configured to: supply gaseous fuel to the
piston-cylinder unit via the gas supply device; during a
steady-state phase, introduce diesel fuel to the piston-cylinder
unit, via the fuel injector, as a pilot fuel injection before top
dead center of an expansion phase of the piston-cylinder unit in
order to initiate combustion of the gaseous fuel; and responsive to
operating in a transient phase, introduce the diesel fuel to the
piston-cylinder unit, via the fuel injector, as the pilot fuel
injection and also as an expansion phase injection in the expansion
phase of the piston-cylinder unit while heat is released from the
combustion of the gaseous fuel.
13. The system of claim 12, wherein the regulating device is
configured to introduce the diesel fuel as the expansion phase
injection by commanding diesel fuel injection via the fuel injector
after top dead center of the expansion phase of the piston-cylinder
unit.
14. The system of claim 12, wherein, during the steady-state phase,
the piston-cylinder unit does not receive the expansion phase
injection.
15. The system of claim 12, wherein the regulating device is
further configured to, responsive to the operation in the transient
phase, change a position of a wastegate and/or a compressor bypass
in a direction of a smaller opening.
16. The system of claim 12, wherein the steady-state phase includes
a current load demand changing by less than an absolute threshold
value and the transient phase includes the current load demand
changing beyond the absolute threshold value.
17. The system of claim 12, wherein the gas supply device comprises
a port-injection valve.
18. The system of claim 12, wherein the gas supply device comprises
a gas mixer positioned upstream of a compressor of a turbocharger.
Description
BACKGROUND OF THE INVENTION
Embodiments of the invention relate to a dual-fuel internal
combustion engine with the features of the preamble of claim 1 and
a method for operating a dual-fuel internal combustion engine with
the features of the preamble of claim 7.
Dual-fuel internal combustion engines are typically operated in two
operating modes. We differentiate an operating mode with a primary
liquid fuel supply ("liquid operation" for short; in the case of
the use of diesel as a liquid fuel, it is called "diesel
operation") and an operating mode with primarily gaseous fuel
supply, in which the liquid fuel serves as a pilot fuel for
initiating combustion (also called "pilot operation", "dual-fuel
operation" or "ignition-jet operation").
In pilot operation mode, in which the liquid fuel is introduced as
a pilot fuel, the regulating device is designed to control the fuel
injector and the at least one gas supply device for selective
metering of the quantity of liquid or gaseous fuel supplied to the
at least one piston-cylinder unit.
In diesel operation, it is known that the combustion process can be
moderated by varying the pilot injections, main injections and
after-injections. Such operating modes with multiple injections are
known e.g. from DE 602 16 437 T2, EP 2 806 140 A1, US 2012/0325180
or WO 2003/027473 A1.
U.S. Pat. Nos. 7,305,972, 7,769,530, DE 10 2014 000 326 A1, DE 10
2014 004 976 A1 and EP 1 730 394 disclose injectors and control
concepts suitable for this purpose.
With regard to the load requirement placed on an internal
combustion engine, a distinction can be made between steady-state
operation and transient phases.
If the load requirement moves within a relatively narrow band (e.g.
if changes in the load requirement are below about 10% of the
current load), this is called steady-state operation.
If there are larger changes in the load requirement, the transition
from the former to the new load requirement is called a transient
phase.
In diesel operation of the internal combustion engine, it is
possible to map rapid changes in the load requirement and the
internal combustion engine thus has favorable behavior in the
transient phase (in short: transient behavior).
In diesel operation, the power is adjusted by adjusting the fuel
quantity (fuel-guided system).
If, however, the internal combustion engine is primarily supplied
with gaseous fuel, rapid adaptation of the power output of the
internal combustion engine to changed load requirements is not
possible. Simply supplying more gaseous fuel is ruled out, since
the internal combustion engine then starts knocking. An internal
combustion engine in pilot operation therefore has an unfavorable
transient behavior.
BRIEF DESCRIPTION OF THE INVENTION
The object of embodiments of the invention is therefore to provide
a dual-fuel internal combustion engine or a method for operating a
dual-fuel internal combustion engine with improved transient
behavior.
This object is achieved by a dual-fuel internal combustion engine
with the features of claim 1 and a method for operating a dual-fuel
internal combustion engine with the features of claim 7.
Developments are indicated in the dependent claims.
By the regulating device in pilot operating mode having an
operating mode in which liquid fuel is supplied in an expansion
phase to the piston-cylinder unit by the fuel injector of the
piston-cylinder unit, improved transient behavior of the internal
combustion engine is achieved. Thus, the internal combustion engine
can continue to be operated in the operating mode with
predominantly gaseous fuel, i.e. it does not have to be switched to
diesel operation, as is the case in the prior art for creating fast
transients.
Especially in so-called fast runners (internal combustion engines
with speeds >approx. 1,200 rpm-1) with a central gas mixer, only
due to the transport delay through the large paths, it is not
possible to change between the operating modes quickly.
Embodiments of the invention make it possible to operate dual-fuel
internal combustion engines in the operating mode with a primary
supply of gaseous fuel with a transient behavior which comes close
to that of diesel engines or dual-fuel internal combustion engines
in diesel operation.
The transient behavior thus obtained is clearly superior to that of
a conventional gas engine (gas Otto internal combustion engine
without the possibility of injection of liquid fuel), with the
emission advantages over a diesel engine or a dual-fuel internal
combustion engine in diesel operation.
Embodiments of the invention are particularly relevant for use with
stationary internal combustion engines and in marine applications.
The internal combustion engines can be used as mechanical drives,
e.g. for operating compressor systems or coupled with a generator
to gensets.
The regulating device is designed such that it remains in the
steady-state operating mode in pilot operating mode until the load
requirement is changed in terms of quantity over a predetermined
threshold value (e.g. more than 10% of the previous or current load
requirement). If the threshold value is exceeded, the regulating
device switches to transient mode until the power provided by the
internal combustion engine falls below a predetermined distance
(e.g. less than 10% of the new load requirement) with respect to
the new load requirement. As soon as this is the case, the
regulating device switches back to steady-state operating mode. Of
course, the bands resulting from the above-defined thresholds may
be selected depending on the quantity of the current or new load
requirement.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention are explained in more detail with
reference to the figures. The drawings in detail:
FIG. 1 shows a diagram of an internal combustion engine,
FIG. 2A, 2B show diagrams of an injection rate and a heat release
rate over the crank angle in steady-state operating mode (FIG. 2A)
and in transient mode (FIG. 2B)
DETAILED DESCRIPTION
FIG. 1 shows schematically an internal combustion engine 1 with a
piston-cylinder unit 2 and a fuel injector 3 for injecting liquid
fuel. Only one piston-cylinder unit 2 is shown by way of example.
In practice, generic internal combustion engines have a plurality
of piston-cylinder units 2.
A regulating device 5 can regulate the quantity of liquid fuel
supplied to the piston-cylinder unit 2 (via the fuel injector 3) or
the supplied quantity of gaseous fuel (via a gas supply device 4).
Signal lines are indicated by dashed lines. In the interest of
clarity, not all signal lines leading to the regulating device 5
are shown.
Exhaust gases from the piston-cylinder unit 2 flow to an
exhaust-gas turbine 8 of a turbocharger 7. A compressor 9 is
connected to the exhaust-gas turbine 8. In the exemplary embodiment
shown, a gas supply device 4 is arranged downstream of the
compressor 9. At this point, the gas supply device 4 may be
designed e.g. as a port-injection valve for the cylinder-specific
metering of gaseous fuel.
In one variant, the gas supply device 4 is arranged upstream of the
compressor 9. At this point, the gas supply device 4 may be
designed e.g. as a gas mixer.
The internal combustion engine 1 or the regulating device 5 is
configured such that, in the expansion stroke (expansion phase) of
the piston-cylinder unit 2, additional liquid fuel can be injected
by the fuel injector 3.
In this phase, the piston 6 of the piston-cylinder unit 2 is
already beyond the top dead center and the risk of knocking is thus
greatly reduced.
In practice, the safe distance (how early the injection may occur
after the top dead center) to the knock limit is determined by
experiments. The safe distance depending on the load can be stored
e.g. as a look-up table in the regulating device.
The distance to the knock limit also depends on the quality of the
gas used as the gaseous fuel. In particular in marine applications,
the gas quality can change due to demixing in the entrained gas. A
routine may be provided to determine the distance to the knock
limit.
The additional introduction of energy in transient mode in the form
of liquid fuel in the expansion phase also causes, in addition to a
higher power delivery (and thus directly increased torque),
increases the enthalpy of the exhaust gas by extending the pressure
phase in the piston-cylinder unit 2. Thus, more energy reaches the
exhaust-gas turbine 8 of the turbocharger 7, and the compression
power of the turbocharger 7 increases faster, which in turn allows
a gas supply to follow faster.
An optionally higher fuel consumption and reduced efficiency when
driving through the transient phase is accepted.
By injecting the liquid fuel in the expansion phase, only a small
increase in NOx emissions can be observed since, in this period,
there are temperature and pressure conditions in which barely any
NOx is formed.
Embodiments of the invention are particularly suitable for a lean
operation with a combustion air ratio lambda of e.g. 1.7 to 1.8.
Even after combustion of a lean mixture with high excess air, a
sufficiently high content of oxygen for oxidation of the liquid
fuel is present. This residual oxygen content is also the limiting
factor for the quantity of additionally injected liquid fuel.
As an additional measure, the residual oxygen content in the at
least one piston-cylinder unit 2 can be increased in the short term
by a wastegate 10 that can be actuated by the regulating device 5,
whereby the quantity of liquid fuel that can be converted in
transient mode can be increased. Instead of a wastegate 10, a
compressor bypass 11 that can be actuated by the regulating device
5 could also be provided for this purpose. Actuation here means a
change in the position of the wastegate 10 or compressor bypass 11
in the direction of a smaller opening. A reduced opening position
increases the lambda in the short term.
FIG. 2A shows an injection rate and a heat release rate plotted
against the crank angle for the steady-state operating mode. The
top dead center at 0.degree. crank angle is marked by a dashed
vertical auxiliary line. The peak detectable in the course of the
injection rate marks the pilot injection.
FIG. 2B shows the injection rate and the resulting heat release
rate over the crank angle according to embodiments of the invention
in transient mode. In the course of the injection rate, in addition
to the peak of the pilot injection, the injection in the expansion
phase can also be seen. It can be seen that, as a result of this
additional injection of liquid fuel in the expansion phase compared
with the pilot injection, the course of the heat release rate drops
less than in the case described in FIG. 2A.
The area under the heat release rate curve can be interpreted as
converted heat. It is clear that significantly more energy is
converted by the inventive measure of the additional injection in
the expansion phase of the internal combustion engine 1 in
dual-fuel operation with gas as the main fuel, which contributes to
a faster response of the turbocharger 7 as stated above.
This written description uses examples to disclose the invention,
including the preferred embodiments, and also to enable any person
skilled in the art to practice the invention, including making and
using any devices or systems and performing any incorporated
methods. The patentable scope of the invention is defined by the
claims, and may include other examples that occur to those skilled
in the art. Such other examples are intended to be within the scope
of the claims if they have structural elements that do not differ
from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal languages of the claims.
* * * * *